Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B14/38—Fibrous materials; Whiskers
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
  • C04B20/10—Coating or impregnating
  • C04B20/1051—Organo-metallic compounds; Organo-silicon compounds, e.g. bentone
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B16/00—Use of organic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of organic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B16/04—Macromolecular compounds
  • C04B16/06—Macromolecular compounds fibrous
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/50—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with organometallic compounds; with organic compounds containing boron, silicon, selenium or tellurium atoms
  • D06M13/503—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with organometallic compounds; with organic compounds containing boron, silicon, selenium or tellurium atoms without bond between a carbon atom and a metal or a boron, silicon, selenium or tellurium atom
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2933—Coated or with bond, impregnation or core
  • Y10T428/2964—Artificial fiber or filament
  • Y10T428/2967—Synthetic resin or polymer
  • Y10T428/2969—Polyamide, polyimide or polyester

Definitions

• This invention relates to coated aramid fibers for cement reinforcement and to fiber-reinforced cement products incorporating such fibers.
• the combination of such coated aramid fibers with a pulp of oriented polyethylene fibrids is particularly useful for this purpose.
• p-aramid fibers are made more suitable for cement reinforcement by coating them with from 0.25 to 40%, preferably from 0.25 to 10% by weight of an alkyl titanate, or a titanium chelate compound.
• the aramid fiber is poly-p-phenylene terephthalamide or a copolymer thereof.
• the invention also includes reinforced cement products containing from 0.1 to 6% by weight of the coated fiber.
• a pulp of oriented polyethylene fibrids is employed in combination with the coated p-aramid fiber for the cement reinforcement.
• cement products reinforced with fibers of p-aramids have previously been suggested, however, there is a need for cement products of greater flexural strength and toughness. Applicant has found that this objective is reached by coating the p-aramid fiber with an alkyl titanate or a titanium chelate compound prior to incorporation in the cement.
• the p-aramid fiber used in the present invention is formed of poly-p-phenyleneterephthalamide prepared from p-phenylene diamine and terephthalic acid or functional equivalents thereof. Better results have been obtained when a copolymer fiber prepared from p-phenylene diamine, terephthalic acid and 2,6-naphthoic acid or functional equivalents thereof is employed. In such copolymers there should be at least 75 mole % terephthalamide and up to 25 mole % of 2,6-naphthalamide units. Certain of the p-aramid fibers are commercially available such as Kevlar® 49 Aramid fiber (E. I. du Pont de Nemours and Company).
• lactic acid titanate chelate ammonium salt also known as titanium lactate, ammonium salt
• Ti lactate titanium lactate
• Other titanates such as the triethanolamine chelate and tetraisopropyl titanate, commercially available as Tyzor® TE and Tyzor TPT from E. I. du Pont de Nemours and Company are also useful.
• Alkyl (of up to 12 carbon atom length groups) titanates such as tetraisopropyl, tetrabutyl and tetrakis (2-ethylhexyl) titanates may be used but are less preferred.
• titanates such as tetraisopropyl, tetrabutyl and tetrakis (2-ethylhexyl) titanates may be used but are less preferred.
• titanates such as tetraisopropyl, tetrabutyl and tetrakis (2-ethylhexyl) titanates may be used but are less preferred.
• from about 0.25 to 10% by weight of the chelate is coated on the p-aramid yarn from aqueous solution.
• the yarn is then dried and cut into staple lengths which for cement reinforcement purposes are generally in the range of from 4 to 20 mm. in length, preferably 5-12 mm. in length.
• Fiber reinforced cement composites were evaluated by determining flexural toughness (also called work-to-break). The test is described in ASTM D-790. Flexural testing is used frequently by the asbestos cement industry as a measure of product performance for sheet products such as roofing tiles, building panels, etc. Cement samples (2.54 cm ⁇ 15.2 cm33 0.5 cm), prepared as described below were tested according to the above ASTM method in 3-point bending in an Instron test machine. A span of 7.6 cm was used in all cases. Test specimens are loaded to failure, and the maximum stress level determined graphically with a chart recorder. Flexural toughness is taken as the integrated area under the stress-strain curve until maximum stress is reached, measured in kJ/sq m (kilojoules per square meter). All samples, including controls were tested in the same way.
• the "flexural strength” sometimes called modulus of rupture is the point of maximum stress in the above test. It is reported in MPa (megapascals).
• aqueous solution of the titanium/lactic acid complex was diluted with one or nine parts of distilled water, depending on whether a high or low level of coating was desired.
• the yarn was a multifilament poly-p-phenyleneterephthalamide yarn having a tensile strength of about 400,000 lb/in 2 and a modulus of about 18 million lb/in 2 .
• the filament denier was between about 1.7 and 2.5 dtex.
• the yarn was formed from a copolymer containing about 80 mole % of p-phenyleneterephthalamide units and about 20 mole % of p-phenylene-2,6-naphthalamide units.
• the yarns were coated by dipping them into the solutions or by passing the yarns over a slotted coating head at 50 yd/min and metering the solutions onto the yarn through a metering pump to produce the desired coating levels. Drying of the yarns was begun by passing them through a heated furnace, over heated rolls or both; furnace/roll temperatures of 100°-200° C. (usually 150° C.) were employed depending on the denier of the yarn and method of application. Conditions were set so as to evaporate most but not all of the solvent water. Final drying was accomplished by transferring the yarns to perforated bobbins and heating them in a vacuum oven at 110° C./20 mm until constant weight was reached (usually overnight). Coating levels were determined by weighing the yarns before and after coating or by calibration of the metering system. Dried yarns were cut into 6 mm staple before use in making cement tiles.
• fiber reinforced cement composites are prepared which contain Portland cement, or mixtures of Portland cement and silica flour, together with various fibrous synthetic materials. Pulps are prepared by placing the unopened pulp (usually 8 gm) into a home blender with 1 l of water and blending on low speed for about 30-90 seconds (pulp all fluffed up). Opened pulps, thus prepared, are added to a plastic bucket containing about 4 l of water and the coated staple fibers. The mix is dispersed for 5 min with gentle agitation using a vibrating laboratory stirrer. Type 1 Portland cement (200 gm), or a mixture of cement and silica (200 gm total), dispersed into a slurry with 1 l of water, is then added.
• Flocculation is induced by addition of 4 ml of a 0.1% solution of flocculating agent (Separan A-273 manufactured by Dow Chemical Co.). The entire slurry is then cast into a sheet 33 cm ⁇ 33 cm and approximately 1.5-2 mm thick by pouring into a standard Deckle box paper making mold and dewatering. The resulting sheet is then folded into four layers, trimmed to 15.2 ⁇ 15.2 cm and pressed in a mold for 30 min at 1667 psi.
• a flocculating agent Separan A-273 manufactured by Dow Chemical Co.
• Example I tiles are prepared for testing by pre-curing the molded composite (removed from the mold) one day at room temperature at about 100% relative humidity followed by curing in a steam autoclave (about 100 psi) at 160° for 6.5 hrs, whereas Example II tiles are cured for 28 days immersed in saturated lime water.
• the cured cement tiles are cut into strips 2.54 cm wide with a diamond saw. The strips are re-immersed in lime water and tested wet in 3-point bending to determine flexural toughness. Flexural strength values are given in MPa units and work-to-break toughness, that is the under the stress-strain curve to maximum stress, are given in KJ/sq m.
• Poly-p-phenylene terephthalamide was cut into 6 mm staple. 8 gm samples were dipped into various coating compositions, removed, drained and kept in an oven at 60° C. overnight. Final sample weights were about 11 gm, indicating that substantial coating had been picked-up by the fiber.
• cement tiles were prepared from 4 gm of the coated staple, 8 gm of newspulp, and 200 gm of type 1 Portland cement. Testing was conducted as indicated above. This example establishes the usefulness of a variety of titanate-coated aramids for cement reinforcement. Average results are indicated:

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Inorganic Chemistry (AREA)
• Textile Engineering (AREA)
• Civil Engineering (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Artificial Filaments (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Cultivation Of Seaweed (AREA)
• Treatment Of Sludge (AREA)
• Multicomponent Fibers (AREA)

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Publications (1)

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Cited By (8)

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Citations (6)

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• 1985
  • 1985-12-20 US US06/811,843 patent/US4693749A/en not_active Expired - Lifetime
• 1986
  • 1986-12-16 CA CA000525496A patent/CA1276087C/en not_active Expired - Lifetime
  • 1986-12-18 JP JP61300176A patent/JPS62158149A/ja active Pending
  • 1986-12-18 AU AU66736/86A patent/AU585790B2/en not_active Ceased
  • 1986-12-19 DK DK618286A patent/DK618286A/da not_active Application Discontinuation
  • 1986-12-19 DE DE8686309960T patent/DE3669705D1/de not_active Expired - Lifetime
  • 1986-12-19 KR KR860010934A patent/KR870005928A/ko not_active Application Discontinuation
  • 1986-12-19 EP EP86309960A patent/EP0227452B1/en not_active Expired - Lifetime

Patent Citations (6)

Non-Patent Citations (4)

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